A study had been conducted to confirm the method of the Signal Averaged Electrocardiography (SAECG); using (XYZ) leads system and a (FIR) filter of (40) Hertz cutoff frequency for signal processing. The value of this method had been tested in 32 patients with Acute Myocardial Infarction (AMI) after being compared to a control group of comparable number, age and sex. The patients are divided into subgroup (I) & subgroup (II) according to the presence or absence of ventricular arrhythmogenic events respectively. The result can be summarized as follows; 1 . The averaged durations of the filtered (F) waves that represent ventricular depolarization in patients group are significantly higher than those for control group. 2 . Analyzing the F.QRS complex we found the following; a . patients with (AMI) had a significantly longer and lower terminal end in their F.QRS complex than control group. b . if we quantify the terminal end of this F.QRS complex by certain durations and amplitudes, we can see that none of these abnormal criteria (amplitudes & durations) are present in control group; while they are present in a high percentage in group (I) of patients with (AMI). c . the high incidence of these abnormal criteria (L.Ps) in patients with (AMI); would make them a sensitive and specific markers for ventricular arrhythmogenicity. d . recording the SAECG at the end of the first week after an attack of AMI; is a good screening test to identify patients at risk of ventricular Arrhythmias.